Russian Prime Minister Dmitry Medvedev sharply denounced the sanctions bill signed into law by U.S. President Donald Trump on August 2, saying it ends hope for improving relations and ignites "an all-out trade war with Russia."

"The hope for improving our relations with the new U.S. administration is now over," Medvedev said on Facebook after Trump reluctantly signed the bill he once opposed, calling it “significantly flawed” and signaling that he might not fully implement the sanctions.

Medvedev attacked Trump's decision to sign the bill in a bow to Congress, where it passed with sizable majorities that ensured lawmakers could override any potential veto. Trump said he wanted to preserve "national unity."

"Trump's administration has demonstrated total impotence by surrendering its executive authority to Congress in the most humiliating way," Medvedev said.

"The American establishment has won an overwhelming victory over Trump. The president wasn't happy with the new sanctions, but he had to sign the bill."

Medvedev said the bill's sanctions, aimed at punishing Russia for allegedly meddling in last year's U.S. presidential election and its military aggression in Ukraine and Syria, will only make Russia grow stronger as it is forced to develop new markets and industries .

"We will continue to work calmly to develop our economy and social sphere, deal with import substitution, and solve important government tasks counting primarily on ourselves," he said. "We have learned how to do it over the past few years."

'Nothing New'

With the sanctions sealed into law, Medvedev said they will aggravate U.S.-Russia relations for years to come and will be almost impossible to reverse.

"The sanctions regime is codified and will be preserved for decades, unless a miracle happens," he said. "Relations between Russia and the U.S. will be extremely tense despite the composition of the Congress or the president's personality."

The Russian Foreign Ministry called the sanctions "short-sighted and dangerous" and said it is reserving the right to impose further countermeasures beyond the expulsion of 755 U.S. diplomatic personnel in that Russia already ordered.

But Kremlin spokesman Dmitry Peskov said no further retaliatory measures from Moscow would be taken immediately, saying "this de-facto changes nothing. There's nothing new... We've already taken retaliatory measures," according to Russian news agencies.

On August 3, Peskov declined to comment on Medvedev’s remarks but said that Russia is determined to “protect and defend its interests," without elaborating.

Moreover, the Russian Foreign Ministry said it remains "open for cooperation with the U.S. in the spheres where we see it [as] useful for ourselves and international security, including the settlement of regional conflicts."

Russian Foreign Minister Sergei Lavrov is due to meet with U.S. Secretary of State Rex Tillerson, who said he's still seeking ways to cooperate with Russia and is "not happy" with the sanctions legislation, on the sidelines of a summit in Asia over the weekend.

U.S. President Donald Trump (file photo)

In a statement accompanying his signature of the sanctions legislation on August 2, Trump said it was “significantly flawed” and would hinder his administration’s ability to negotiate with foreign adversaries.

“My administration will give careful and respectful consideration to the preferences expressed by the Congress in these various provisions and will implement them in a manner consistent with the president’s constitutional authority to conduct foreign relations,” he said in a statement released by the White House.

“My administration particularly expects the Congress to refrain from using this flawed bill to hinder our significant work with European allies to resolve the conflict in Ukraine and from using it to hinder our efforts to address any unintended consequences it may have for American businesses, our friends, and our allies,” he said.

But Trump conceded that the bill "represents the will of the American people to see Russia take steps to improve relations with the United States. We hope there will be cooperation between our two countries on major global issues so that these sanctions will no longer be necessary," he said.

"I built a truly great company worth many billions of dollars. That is a big part of the reason I was elected. As president, I can make far better deals with foreign countries than Congress," Trump said.

The law cements into place an array of sanctions imposed on Russia by Trump's predecessor, Barack Obama, for Moscow’s alleged meddling in the 2016 presidential election, the annexation of Ukraine's Crimean Peninsula, and its support for separatists fighting Ukrainian government forces in eastern Ukraine.

Among other things, the measure targets Russian energy firms with new financial sanctions, something that several U.S. allies in Europe had spoken out strongly against. Several German companies in particular have said they could be penalized for working on a pipeline being built under the Baltic Sea to bring Russian gas directly to Germany.

U.S. lawmakers modified the bill after initial complaints by European leaders, which appeared to mollify Brussels.

EU Misgivings

Still, European Commission President Jean-Claude Juncker warned on August 2 after the legislation was signed that European energy companies could be harmed, particularly those working on Russian natural-gas pipeline systems that transit Ukraine to reach EU member states.

“If the U.S. sanctions specifically disadvantage EU companies trading with Russia in the energy sector, the EU is prepared to take appropriate steps in response within days,” Juncker said in a statement.

Germany’s economics minister had earlier urged the European Union to fight back against the sanctions.

In Kyiv, Ukraine's president hailed the measure, and he singled out the undersea Nord Stream 2 pipeline, which he called a "politically motivated project."

The sanctions "will be effective in [achieving] the full liberation of Ukrainian land," Petro Poroshenko wrote in a comment on his Facebook page. “This is yet another confirmation of the strategic direction in relations being taken by Ukraine and the United States.”

The new law also imposes tough new sanctions on Iran and North Korea over their missile programs, as well as for human rights abuses by Iran's Islamic Revolutionary Guards Corps, one of Tehran's most powerful military and security organizations.

Iran on August 1 formally complained to the United Nations about the legislation, accusing the United States of violating its commitments under a nuclear agreement reached with six world powers